The present invention relates to the operation of a DC motor system, and more particularly to a method and system for determining, with an ascertained statistical confidence, the reliability of a component with the DC motor system.
Acquisition of accurate information concerning the running condition, status, and performance of DC motor systems, such as, but not limiting of, electric motors used in industrial manufacturing processes, power generation systems, or the like; is often crucial in maintaining successful operation of such systems. Consequently, considerable efforts are often expended to develop and improve upon existing methods and systems used for assessing the operation and performance of electric motors and coil devices in such systems. Robust methods of inspection are often desired for such critical process motors, since inoperability of a motor may adversely impact revenue generation.
Robust processes for the inspection and predictive maintenance of DC motor systems usually involve monitoring a variety of operational indicators to detect an impending failure and may also be used for determining reliability. Conventionally, one or more indicators are monitored over time and used to trigger a maintenance outage/recommendation when the value of a monitored parameter exceeds a predetermined threshold. The contemporary technological trend is to automate the inspection process by affixing a variety of sensors and transducers to the DC motor to continuously collect information through either off-line monitoring or on-line monitoring techniques. Operational indicators for an operating motor may then be tracked continuously and an alarm may be immediately triggered if a predetermined threshold value for a particular indicator is exceeded. For example, but not limiting of, vibration amplitude or spectral data that exceeds or drifts from a predetermined range or value can be used to activate an alarm to notify the equipment operator that a particular type of failure mode is imminent.
The use of motor operational indicator data as a failure predictive tool and to assess motor health has been explored to some extent in the past by various investigators. Different DC motor system indicators may sense vibration, temperature, and speed for this purpose and may include at least one device integrated with the DC motor for detecting issues with the commutator, arcing, and/or sparking issues, etc.
In general, service and repair information acquired as a result of previous inspections and routine maintenance of motor equipment is not compiled for the purpose of performing predictive/prognostic maintenance or conducting a comprehensive analysis of motor health. Conventionally, a DC motor system expert/specialist simply assesses available historical information and then formulates a maintenance recommendation based on obvious trends and personal experience. A decision to repair or perform maintenance is commonly based on an estimate of the reliability developed primarily from the subjective judgment of the expert. In other instances, preventive maintenance is based solely on the number of hours of motor operation or the time since the last maintenance outage, rather than on any condition-based test results.
There are a few drawbacks with the currently known methods of monitoring and diagnosing the reliability of a DC motor system. The conventional systems typically target only data that may represent an imminent failure and do not provide a quantitative determination of remaining motor life or motor reliability. Some conventional systems provide only a general warning of imminent motor failure based on the detection of an alarm condition from a single monitored indicator. These systems may not provide an assessment of motor reliability, nor do they provide an estimate of the operating time remaining until a repair will be needed.
For the foregoing reasons, there is a need for a method and system for determining the reliability of a DC motor system. The method and system should receive a plurality of operating data on the components of the DC motor system. The method and system should also analyze motor data and determine the motor reliability.